Robbins Double Shield Completes Marathon Mileage
March 31, 2011
More than 500 people gathered at the breakthrough ceremony in a remote area of Shanxi Province to mark the occasion. “The key to this project’s success was the crew. We had the right mix of experienced people and young people hungry to learn,” said Paul Bargmann, Head of the Machinery Dept. for Alpine Bau GmbH. The Robbins machine successfully mined through difficult geology including coal seams and abrasive sandstone with up to 70 percent quartzite content. Advance rates topped out at 50 ring sets, or about 70 m (230 ft), per day.
Though the TBM was already designed for similar geology and kept to its original specifications for the Pinglu Tunnel, the back-up was modified. “The back-up frame was extended from one stroke to two strokes. This was a key change, especially for such a long tunnel,” said Meik Mueller, Technical Director for Alpine’s Asia Division. The modification allowed the machine to maintain good advance rates despite transit times of up to 70 minutes for muck trains traveling from the machine to tunnel entrance.
The completed Pinglu Tunnel will go into operation in October 2011, connecting to the North Main Line of the Yellow River Project to transfer water to Pinglu, Shuozhou, and Datong areas. More than 100 km (62 mi) of the South Main Line were excavated by five TBMs, including four Robbins Double Shields, between 1999 and 2001. The entire scheme will transfer water from the Yellow River to dry regions of Shanxi Province, an area that receives just 400 mm (16 in) of rainfall per year on average.
This article was supplied by The Robbins Co.